Blind cavity and micro-groove component drying device and drying method for fluid circuit

Abstract

The present invention provides a drying device and method for blind cavity and microgroove components used in fluid circuits. The device comprises: a container for placing the components to be dried; an air source for providing clean, dry air to the container; a hot air circulation module for heating the gas inputted into the container by the air source and forcing convection circulation of the heated gas to ensure a temperature uniformity within the container of less than 2°C; a gas compression supply and blow-off module for pressurizing the gas within the container and blowing and drying the components placed within the container through pipelines; a vacuum pump assembly for evacuating the interior of the container; and a vacuum infrared heating module for applying heat input to the components placed within the container to increase the temperature of the components. This device achieves rapid drying of blind cavity and microgroove components, helping to shorten drying time and improve drying efficiency. Furthermore, vacuum and concentration detection and drying determination devices can effectively determine the dryness of the components.

Description

Technical Field

[0001] The present invention relates to the technical field of drying blind cavities and micro-groove portions of fluid circuit systems, and specifically to a drying device and a drying method for blind cavity and micro-groove portion components for fluid circuits, and especially to a drying device and a drying method for blind cavity and micro-groove portion components for spacecraft fluid circuits. Background Art

[0002] Fluid circuits are used to collect and transmit heat from high-power equipment in spacecraft. They are mainly composed of cold plates, drive pumps, filters, one-way valves, self-locking valves, pressure sensors, liquid reservoirs, radiators, connecting pipes, etc. The main working principle is that the pump drives the working fluid to circulate in a closed piping system, bringing the equipment heat from the cold plate to the radiator for dissipation.

[0003] During the development process, component drying requires two stages. The first stage is before the components are welded together into the system. Pumps, valves, filters, and other components with blind cavities and micro-grooves are cleaned and dried after cleaning. The cleaning fluid is generally high-purity water or anhydrous ethanol. The second stage is after the system is integrated and filled. For testing purposes, the system needs to be drained and dried again. Due to the multiple parallel branches in the valve and piping system and the presence of blind-end components such as pressure transmitters and liquid reservoirs, the fluid accumulated in the blind pipes and blind cavities is difficult to remove with nitrogen. Furthermore, the working fluid is a non-volatile ethylene glycol aqueous solution, making it difficult to effectively dry the system. The drying cycle can take from two weeks to one month.

[0004] The drying principle is the evaporation of liquid into gas. Drying primarily relies on temperature differences and gas partial pressure differences. The drying rate is primarily influenced by three factors: the initial amount of liquid; the boiling point of the liquid working fluid; and the evaporation rate when both gas and liquid coexist. Evaporation is a dynamic process of vapor-liquid phase transition, and the evaporation rate is affected by temperature (energy input) and the vapor partial pressure above the liquid surface. Increasing the temperature and decreasing the vapor partial pressure above the liquid surface can accelerate the evaporation rate.

[0005] The drying equipment generally used in the existing technology is a hot air circulation oven. Due to the presence of electrical devices and rubber sealing elements inside the components, the drying temperature generally cannot exceed 60°C. It is relatively simple to dry components with openings at both ends. For components with blind tubes and blind cavities with small openings, such as pressure sensors and liquid reservoirs, the small opening diameter is 4mm. The working fluid absorbs heat and evaporates, accumulating in the inner cavity to form saturated steam, which is difficult to discharge through the blind hole, reducing the evaporation rate of the surface molecules of the liquid in the cavity, making it difficult to further dry. Drying is more difficult, and simply extending the time cannot completely dry the components. In addition, the boiling point of ethylene glycol working fluid is high and it is difficult to volatilize.

[0006] For components with enhanced heat exchange micro-grooves in the inner cavity, the surface tension of the working fluid forms a capillary adsorption effect on the micro-grooves. In addition, the inner cavity has a complex topological structure, the flow resistance is large, and it is difficult for the airflow to form an effective blowing and carrying speed. The working fluid is difficult to be effectively blown away before the product enters the oven, and the working fluid is adsorbed inside the micro-grooves, which reduces the evaporation surface area and the evaporation drying rate.

[0007] like Figure 1 As shown, the working fluid or replacement solution in the blind cavity component cannot be completely and effectively discharged. Instead, it is adsorbed on the wall surface and corrugated grooves through capillary action, and the contact surface with the gas is small. Using a conventional hot air circulation oven, the hot air cannot enter the cavity through the small holes. By exchanging heat with the component body, the temperature of the component is increased, and the working fluid or replacement solution remaining in the blind cavity is heated through the component wall. Because the components cannot be heated to very high temperatures during use, generally a maximum of 60°C, the evaporation rate of the residual liquid in the cavity is not high. The evaporated liquid accumulates in the cavity and gradually forms a high-concentration saturated vapor that is difficult to discharge through the blind hole. The increase in the gas vapor partial pressure reduces the evaporation rate of the surface molecules of the liquid in the cavity, making it difficult for the residual liquid to evaporate and dry further, resulting in difficult drying and a long drying time. Simply extending the drying time is extremely costly, and other means must be considered for efficient drying.

[0008] System components that integrate a liquid reservoir and multiple pressure transmitters have complex piping configurations, with numerous blind pipes and cavities, making effective drying more difficult. Conventional drying ovens struggle to efficiently and quickly dry components with blind cavities and holes, resulting in long drying times and incomplete drying. This leaves room for improvement. Summary of the Invention

[0009] In view of the defects in the prior art, the present invention aims to provide a drying device and a drying method for a blind cavity and micro-groove portion assembly for a fluid circuit.

[0010] According to the present invention, a blind cavity and micro-groove component drying device for a fluid circuit includes: a container: used to place components to be dried; an air source: used to provide clean, dry gas to the container; a hot air circulation module: used to heat the gas input into the container by the air source, and also used to force convection circulation of the heated gas to ensure that the temperature uniformity in the container is less than 2°C; a gas compression and air blowing module: used to pressurize the gas in the container and blow and dry the components placed in the container through pipelines; a vacuum pump group: used to evacuate the interior of the container; and a vacuum infrared heating module: used to apply heat input to the components placed in the container to increase the temperature of the components.

[0011] Preferably, the container includes a tank door, and the outer wall of the container is covered with a thermal insulation layer; a cold trap collector is provided inside the container, and the cold trap collector is provided at the communication port between the vacuum pump group and the container.

[0012] Preferably, the gas source and the container are connected through an air supply pipeline, and the air supply pipeline includes a main air supply pipeline and a bypass air supply pipeline; the main air supply pipeline includes a pressure reducing valve, a filter and a pulse control valve connected in sequence from the gas source to the container; the bypass air supply pipeline includes a pressure reducing valve, a filter and a microflow valve connected in sequence from the gas source to the container.

[0013] Preferably, the air supply pipeline also includes an air supply pipe extending into the container; the hot air circulation module includes an electric heating element and a fan, and the electric heating element is connected to the air supply pipe; the fan is directly opposite the component, used for forced circulation of heated gas, and used for hot air circulation drying of components.

[0014] Preferably, the gas compression supply and blowing module includes an air compressor, which compresses the gas in the container, and the outlet of the air compressor is connected to the air supply pipe.

[0015] Preferably, it also includes a concentration detection and drying judgment device: used to detect the gaseous concentration of the working fluid at the blow-off outlet of the component and the gaseous concentration of the working fluid inside the container; the concentration detection and drying judgment device includes a concentration detector, and one or more concentration detectors are placed at the blow-off outlet of the component and in the container respectively.

[0016] Preferably, the judgment relationship of the concentration detection and drying determination device is as follows:

[0017] For the hot air circulation stage:

[0018] satisfy Enter the next stage;

[0019] in, represents the concentration index of the ith concentration detection point; c represents the drying judgment threshold value of the set hot air circulation stage;

[0020] For the vacuum heating stage:

[0021] satisfy ; Determine whether the drying of the components is completed;

[0022] Wherein, x is a dimensionless index parameter in the vacuum drying stage, representing the difference in working fluid vapor concentration or partial pressure between the outlet of the component and the interior of the container; a and b are both the extreme drying thresholds for vacuum heating.

[0023] Preferably, it also includes a vacuum degree detection and dryness determination device: used to detect the vacuum degree of the product blow-off outlet and the vacuum degree inside the container; the vacuum degree detection and dryness determination device includes a vacuum gauge, and at least one vacuum gauge is placed inside the container and at the outlet of the component respectively.

[0024] Preferably, the drying degree judgment relationship for the vacuum degree detection and drying judgment device is as follows:

[0025] satisfy ;

[0026] Where y is a dimensionless parameter of vacuum drying, which represents the difference in vacuum degree between the outlet of the component and the inside of the container. is the vacuum degree of the i-th vacuum gauge measuring point, is the saturated vapor pressure of the working medium at 15℃~25℃, d is the judgment threshold of the dimensionless parameter y, and when y is less than d, it is determined that the drying of the component is completed.

[0027] According to the present invention, a drying method for a blind cavity and micro-groove portion drying device for a fluid circuit is provided, the drying method comprising the following steps:

[0028] Step S1: Use high-purity nitrogen to pressurize and blow out the interior of the blind cavity or micro-groove component to discharge the liquid working medium filled inside;

[0029] Step S2: filling the blind cavity or micro-groove component with another liquid solvent that is mutually soluble and volatile with the working medium to perform mutual dissolution and replacement, and blowing out with nitrogen to carry out the non-volatile working medium;

[0030] Step S3: Place the components to be dried in the container, connect the air outlet of the air supply pipe of the components, and close the tank door;

[0031] Step S4: Open the gas source to fill the container with dry nitrogen;

[0032] Step S5: Start the hot air circulation device to heat to the set temperature for hot air circulation drying, and dry for a certain time;

[0033] Step S6: Start the compressed gas supply blowing module to blow away the component products;

[0034] Step S7: Open the exhaust valve to discharge the hot and humid nitrogen containing the working fluid steam after operation;

[0035] Step S8: Repeat the steps S4 to S7 to determine whether the concentration of the working medium vapor contained in the high-purity nitrogen gas in the container reaches the set value through the working medium concentration detection device and the drying determination device. If so, proceed to the next step; if not, repeat the steps S4 to S7.

[0036] Step S9: closing the hot air circulation module and the gas compression supply and blowing module, discharging the hot and humid nitrogen containing the working fluid steam, and closing the outlet valve;

[0037] Step S10: Start the vacuum unit, turn on the vacuum infrared heating module, and heat to the set temperature;

[0038] Step S11: As the working fluid evaporates, the vacuum degree in the container continues to decrease. When the vacuum degree decreases to near the saturated vapor pressure of the working fluid, the residual liquid working fluid evaporates, and the vacuum degree will have a plateau period. During the plateau period, the bypass gas supply line of the gas source is opened to replenish high-purity nitrogen gas into the interior of the component, forming a micro-flow passing through the inner cavity of the component, carrying out the working fluid gas molecules in the cavity of the component, reducing the working fluid vapor partial pressure in the inner cavity of the component, and further increasing the evaporation rate of the working fluid under low vacuum conditions; when the vacuum degree in the container continues to decrease after passing through the plateau period, it indicates that the working fluid is almost completely evaporated; at the same time, the values ​​of the concentration detection and drying judgment device are monitored. When the absolute values ​​of the product outlet and the concentration detection device inside the container decrease to a certain value, and the difference between the two values ​​is less than a certain ratio, it proves that the drying of the component is completed;

[0039] Step S12: Fill with high-purity nitrogen to restore normal pressure, open the exhaust port, open the tank door, take out the product, and complete the drying process.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The present invention uses a container to place components that need to be dried, an air source to provide clean and dry gas to the container, a hot air circulation module to heat the gas input into the container by the air source, and also to force convection circulation of the heated gas to ensure that the temperature uniformity in the container is less than 2°C, a gas compression and air blowing module to pressurize the gas in the container, blow and dry the components placed in the container through pipelines, a vacuum pump group to vacuum the inside of the container, and a vacuum infrared heating module to apply heat input to the components placed in the container to increase the temperature of the components, thereby achieving rapid drying of blind cavity and micro-groove components, which helps to shorten the drying time and improve the drying efficiency.

[0042] 2. The present invention can effectively judge the dryness of components through the vacuum detection and concentration detection drying judgment device. Due to the existence of blind cavities and micro-grooves, the endoscope probe cannot enter and the internal conditions cannot be effectively observed. The traditional drying method cannot accurately judge the dryness and can only control the temperature and time through experience.

[0043] 3. The present invention reduces the partial pressure of the drying process through vacuum micro-airflow. During the vacuum heating and drying process, a micro-flow valve is used to supplement a small amount of high-purity nitrogen into the component. Under the action of the vacuum unit, a micro-flow is formed through the inner cavity of the component to carry out the working fluid gas molecules, reduce the working fluid vapor partial pressure in the inner cavity of the component, and further improve the evaporation rate of the working fluid under low vacuum conditions.

[0044] 4. The present invention sets a cold trap collector and can adopt various forms such as liquid nitrogen, compressor refrigeration, thermoelectric refrigeration, etc. according to needs, so that the working fluid vapor molecules can be adsorbed and condensed on the low-temperature cold trap surface, quickly adsorbing the residual working fluid of moisture and ethylene glycol, further reducing the working fluid vapor partial pressure and further shortening the drying time.

[0045] 5. The present invention is extensible and versatile, and has a wide range of applications. It is suitable for complex precision valves and devices with micro-grooves, micro-holes, blind cavities, and blind ends, as well as compact pump, valve, and pipeline assemblies integrated with these valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0047] Figure 1 This invention mainly embodies the drying schematic diagram of a general drying equipment in the background technology;

[0048] Figure 2 This is a schematic diagram of a drying device in the first embodiment of the present invention;

[0049] Figure 3 The present invention mainly embodies a schematic diagram of a drying device with a cold trap collector.

[0050] As shown in the figure:

[0051] DETAILED DESCRIPTION

[0052] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0053] Example 1

[0054] like Figure 2 and Figure 3 As shown, a blind cavity and micro-groove component drying device for a fluid circuit provided by the present invention includes an air source 1, a container 2, a hot air circulation module 3, a gas compression supply and blowing module 4, a vacuum pump group 5, a vacuum infrared heating module 6, a concentration detection and drying judgment device 7, and a vacuum degree detection and drying judgment device 8.

[0055] Container 2 is used to place components that need to be dried. Gas source 1 is used to provide clean, dry gas to container 2. Hot air circulation module 3 heats the gas input into container 2 from gas source 1, and is also used for forced convection circulation of heated gas to ensure that the temperature uniformity in container 2 is less than 2°C. Gas compression supply and blowing module 4 is used to pressurize the gas in container 2 and blow and dry the components placed in container 2 through pipelines. Vacuum pump group 5 is used to evacuate the interior of container 2. Vacuum infrared heating module 6 applies heat input to the components placed in container 2 to increase the temperature of the components.

[0056] Specifically, container 2 includes a door 21, and the outer wall of container 2 is coated with a thermal insulation layer. A feasible implementation is that container 2 takes the form of a cylindrical horizontal tank with a diameter of one meter and a length of one meter. Door 21 is provided at one end of container 2 for accessing components and cleaning the tank interior. The tank can withstand vacuum and positive pressure in the range of -0.1 MPa to 0.2 MPa and is equipped with a safety valve. Container 2 is used to store components that need to be dried. The exterior of container 2 is coated with a thermal insulation layer to ensure a high temperature environment inside container 2 during the hot air circulation heating process. A pressure- and vacuum-resistant electrical connector flange is provided on the tank wall for connecting power and signal cables inside the tank to the outside of the tank. The tank wall also includes an inlet for the air source 1, an inlet and outlet for the air compressor unit, an exhaust valve, and a flange interface for the vacuum pump unit 5. Pirani resistance vacuum gauges are placed at multiple points within the tank, and a pressure gauge is installed on the pipe wall to monitor the vacuum and pressure within the pipe.

[0057] Gas source 1 and container 2 are connected via a gas supply pipeline, which includes a main gas supply pipeline and a bypass gas supply pipeline. The main gas supply pipeline includes a pressure reducing valve 11, a filter 12, and a pulse control valve 13, which are connected in sequence from gas source 1 to container 2. The bypass gas supply pipeline also includes a pressure reducing valve 11, a filter 12, and a microflow valve 14, which are connected in sequence from gas source 1 to container 2. Gas source 1 uses high-purity nitrogen, which can provide clean and dry gas to container 2. The outlet of gas source 1 is equipped with a pressure reducing valve 11. The gas source 1 pipeline uses stainless steel bellows and is equipped with a 10μm gas filter 12 to ensure the cleanliness of the product inside container 2 and prevent the introduction of unwanted substances to contaminate the product.

[0058] The air supply pipeline also includes an air supply pipe extending into the container 2. The hot air circulation module 3 includes an electric heating element 31 and a fan 32, and the electric heating element 31 is connected to the air supply pipe. The fan 32 is directly opposite the component and is used for forced circulation of heated gas, and is used for hot air circulation drying of the components. A feasible implementation method is: the electric heating element 31 is an electric heating wire, the fan 32 is a centrifugal fan 32, powered by 220V, with a heating power consumption of 5000W, multiple temperature measuring points are set inside the container 2, and a temperature measuring point is set on the component to be dried. The heating power is closed-loop controlled by the platinum resistor inside the container 2, and the heating temperature is adjustable. The centrifugal fan 32 is used for forced convection circulation of the heated gas to ensure that the temperature uniformity in the tank is <2°C. At the same time, the high-speed hot air flow formed is beneficial to the heat exchange of the same components and enhances the drying effect.

[0059] The gas compression supply and blowing module 4 includes an air compressor, which compresses the gas in the container 2, and the outlet of the air compressor is connected to the air supply pipe. The air compressor uses an oil-free and silent 40L air compressor, which sucks hot nitrogen from the inside of the container 2, pressurizes it to 0.7MPa, and then connects to the container 2 through the air supply pipe and connects to the inlet of the component. For blind cavity devices, a nozzle is inserted into the blind cavity and discharged from the gap between the nozzle and the blind hole. For micro-groove components, the pipeline is sealed and connected to the inlet of the component, and the air flow is discharged from the outlet of the micro-groove component. The pressurized hot nitrogen blows and dries the inside of the dried component in the container 2. Pressurization is conducive to increasing the flow velocity of the inner wall and inner cavity of the blown component, increasing the heat exchange capacity of the high-temperature gas and the drying component, and accelerating the evaporation of the liquid film attached to the wall. The rapid airflow formed by pressurization forms a shear force on the liquid attached to the micro-groove by capillary action. When it is greater than the capillary force, it plays a role of carrying and blowing, reducing the amount of liquid accumulated in the capillary structure, and accelerating the drainage and drying of the component. An electromagnetic pulse control valve 13 is provided at the blowing port, and the pulse frequency can be adjusted using a controller, with a pulse duration of 0.1 to 10 seconds.

[0060] Vacuum pump assembly 5 is used to evacuate the interior of container 2. Its vacuum capacity matches the internal volume of container 2, achieving a maximum vacuum capacity of less than 0.01 Pa. It utilizes an oil-free scroll vacuum pump and a turbomolecular pump, with the oil-free scroll vacuum pump serving as the roughing pump for the foreline and the turbomolecular pump as the main pump. This prevents contamination of components by oil return.

[0061] The vacuum infrared heating module 6 utilizes a halogen quartz infrared lamp array, with a reflector mounted on the back of each lamp. The halogen lamps are placed side by side on a prefabricated rack, connected in parallel, and powered by a 110V DC programmable power supply. Heating power is controlled in a closed-loop manner by thermocouples attached to the components, ensuring the components maintain a set temperature of 55°C.

[0062] The concentration detection and drying determination device 7 is used to detect the gaseous concentration of the working fluid at the blow-off outlet of the subassembly and the gaseous concentration of the working fluid within container 2. This device 7 includes one or more concentration detectors, one each placed at the blow-off outlet of the subassembly and within container 2. These concentration detectors are water vapor concentration detectors, one each at the gas outlet of the subassembly and at the outlet of the vacuum pump assembly 5 of container 2, to monitor the water vapor concentration in real time. Initially, as the vacuum level decreases, water evaporates into water vapor, increasing the specific gravity of water vapor in container 2 and causing the water vapor concentration meter reading to increase. When the water vapor concentration meter reading within the tank begins to decrease, the working fluid is gradually being dried out by the vacuum. Because the liquid working fluid primarily resides within the subassembly cavity, the concentration at the subassembly outlet is greater than the concentration within the tank. When the concentration at the subassembly outlet approaches the concentration within the tank, and both values ​​are below a set value b (where b is the volume percentage of the working fluid in parts per million), and the dimensionless parameter x representing the difference between the two values ​​is less than a certain ratio a, the subassembly drying is complete.

[0063] The judgment relationship of the concentration detection and drying judgment device 7 is as follows:

[0064] For the hot air circulation stage:

[0065] satisfy Enter the next stage;

[0066] in, represents the concentration index of the ith concentration detection point; c represents the drying judgment threshold value of the set hot air circulation stage;

[0067] For the vacuum heating stage:

[0068] satisfy ; Determine whether the drying of the components is complete.

[0069] Wherein, x is a dimensionless index parameter in the vacuum drying stage, representing the difference in working medium vapor concentration or partial pressure at the outlet of the component and inside the container 2; a and b are both extreme drying determination thresholds of vacuum heating.

[0070] The vacuum degree detection and dryness determination device 8 is used to detect the vacuum degree of the product blow-off outlet and the vacuum degree inside the container 2. The vacuum degree detection and dryness determination device 8 includes a vacuum gauge, and at least one vacuum gauge is placed inside the container 2 and at the component outlet.

[0071] The drying degree judgment relationship of the vacuum degree detection and drying judgment device 8 is as follows:

[0072] satisfy ;

[0073] Where y is a dimensionless parameter of vacuum drying, which represents the difference in vacuum degree between the outlet of the component and the inside of the container 2. is the vacuum degree of the i-th vacuum gauge measuring point, is the saturated vapor pressure of the working medium at 15℃~25℃, d is the judgment threshold of the dimensionless parameter y, and when y is less than d, it is determined that the drying of the component is completed.

[0074] The present invention also provides a drying method for a blind cavity and micro-groove portion drying device for a fluid circuit, using the above-mentioned blind cavity and micro-groove portion drying device for a fluid circuit, and the drying method comprises the following steps:

[0075] Step S1: Use high-purity nitrogen to pressurize and purge the interior of the blind cavity or microgroove component to expel the liquid working medium inside. Specifically, 0.1MPa high-purity nitrogen is connected to the inlet of the microgroove component, and the liquid working medium inside is discharged from the outlet. The liquid working medium is ethylene glycol water solution. For the blind cavity component, with the open tube facing downward, a slender nozzle connected to 0.1MPa high-purity nitrogen is inserted into the blind cavity, and the ethylene glycol water solution working medium is discharged from the gap between the nozzle and the open tube.

[0076] Step S2: A different liquid solvent that is miscible and volatile with the working fluid is injected into the blind cavity or microgroove component to dissolve and displace the working fluid. This solvent is then blown out with nitrogen to remove the non-volatile working fluid. Specifically, pure deionized water is used to displace the working fluid multiple times within the component cavity to remove the non-volatile ethylene glycol and reduce the concentration of ethylene glycol in the residual liquid.

[0077] Step S3: Place the components that need to be dried in the container 2, connect the air outlet of the component air supply pipe, and close the tank door 21. Specifically, place multiple component products that need to be dried in the container 2, and connect the components to the nitrogen blow-off outlet of the air supply pipe in the device. The blind cavity components are connected by nozzle insertion, and the micro-groove components are connected by inlet air intake and outlet exhaust. Take effective fixing measures for the products and the blow-off pipeline to prevent the impact of high-speed airflow from causing the product to fall and the pipeline to shake. Close the tank door 21 of the drying device and lock the flange.

[0078] Step S4: Open the gas source 1 to fill dry nitrogen into the container 2. Specifically, open the gas source 1 to fill the drying device container 2 with 0.2 MPa dry high-purity nitrogen through the pressure reducing valve 11.

[0079] Step S5: Start the hot air circulation device to heat to the set temperature for hot air circulation drying, and dry for a certain time. Specifically, start the hot air circulation device to heat, and set the heating temperature to 60°C, and perform hot air circulation drying for 1 hour.

[0080] Step S6: Start the compressed gas supply and blowing module 4 to blow away the component products. Specifically, start the compressed gas supply and blowing module 4 with a compression pressure of 0.7MPa to blow away the component products. During the blowing process, start the electromagnetic relay and set the pulse time to 0.5s to form a pulsed airflow. The blind cavity component and the micro-groove component are heated by a high-speed hot nitrogen airflow to accelerate the evaporation of residual deionized water, and the pulsed airflow is used to carry and blow away excess deionized water. The high-temperature nitrogen inside the container 2 forms a circulating airflow driven by the compressor unit. As the deionized water inside the component evaporates, the concentration of water vapor in the high-purity dry nitrogen gradually increases. The high-concentration water vapor partial pressure is not conducive to the further evaporation of the deionized water inside the component. It is necessary to discharge the nitrogen after work inside the container 2 and refill it with dry nitrogen to repeat the drying and blowing.

[0081] Step S7: Open the exhaust valve to discharge the hot and humid nitrogen containing the working medium steam after the operation. Specifically, close the hot air circulation device and the gas compression supply and blowing module 4, open the exhaust valve of the drying device container 2, and discharge the hot and humid nitrogen after the operation.

[0082] Step S8: Repeat the operation according to step S4-step S7, and determine whether the concentration of the working fluid vapor contained in the high-purity nitrogen in the container 2 reaches the set value through the working fluid concentration detection device and the drying judgment device. If it reaches the set value, proceed to the next step. If it does not reach the set value, repeat step S4-step S7. Specifically, according to step S4 and step S7, the hot nitrogen is blown out again. The second blow can further dry the working fluid inside the component. Through the working fluid concentration detection device, the concentration of the working fluid vapor contained in the high-purity nitrogen in the container 2 will be significantly reduced. If the concentration in the container 2 is still high, the number of repetitions can be increased until the concentration is significantly reduced and the data of the two concentration detectors reach below the set threshold value c, that is, , go to the next step.

[0083] Step S9: close the hot air circulation module 3 and the gas compression supply and blowing module 4, discharge the hot and humid nitrogen containing the working fluid steam, and close the outlet valve.

[0084] Step S10: Start the vacuum unit, turn on the vacuum infrared heating module 6, and heat to a set temperature of 50°C.

[0085] Step S11: As the working fluid evaporates, the vacuum degree in the container 2 continues to decrease. When the vacuum degree drops to near the saturated vapor pressure of the working fluid, the residual liquid working fluid evaporates, and the vacuum degree will have a plateau period. During the plateau period, the bypass gas supply line of the gas source 1 is opened to supplement high-purity nitrogen gas into the interior of the component, forming a micro-flow passing through the inner cavity of the component, bringing out the working fluid gas molecules in the cavity of the component, reducing the working fluid vapor partial pressure in the inner cavity of the component, and further improving the evaporation rate of the working fluid under low vacuum conditions; when the vacuum degree in the container 2 continues to drop after passing through the plateau period, it indicates that the working fluid is almost completely evaporated; at the same time, the value of the concentration detection and drying judgment device 7 is monitored. When the absolute values ​​of the product outlet and the concentration detection device inside the container 2 are reduced to a certain value, and the difference between the two values ​​is less than a certain ratio, it proves that the drying of the component is completed.

[0086] The drying of the components is completed. The calculation formula is as follows:

[0087]

[0088] Wherein, x is a dimensionless index parameter in the vacuum drying stage, representing the difference in working medium vapor concentration or partial pressure at the outlet of the component and inside the container 2; a and b are both extreme drying determination thresholds of vacuum heating.

[0089] Step S12: Fill with high-purity nitrogen to restore to normal pressure, open the exhaust port, open the tank door 21, remove the product, and complete the drying process. Specifically, turn on the nitrogen source 1, fill the drying device container 2 with high-purity nitrogen and restore it to normal pressure, open the exhaust port, open the tank door 21, remove the product, and complete the rapid drying process.

[0090] Example 2

[0091] like Figure 3 As shown in the figure, based on Example 1, a blind cavity and microgroove assembly drying device for a fluid circuit according to the present invention is provided. A cold trap 22 is provided inside the container 2, and the cold trap 22 is arranged at the connection between the vacuum pump assembly 5 and the container 2. Liquid nitrogen, compressor refrigeration, thermoelectric refrigeration, and other methods can be used as needed to allow the working fluid vapor molecules to be adsorbed and condensed on the low-temperature cold trap surface, rapidly absorbing residual water and ethylene glycol, further reducing the working fluid vapor partial pressure and further shortening the drying time.

[0092] The vacuum detection and dryness determination device includes at least two vacuum gauges for determining the dryness based on vacuum detection. The first vacuum gauge is placed inside container 2, and the second vacuum gauge is placed at the component outlet, respectively detecting the vacuum level inside container 2 and the vacuum level at the product outlet. At least these two sampling points are set up to determine the dryness level, and the determination relationship is as follows:

[0093]

[0094] Where y is a dimensionless parameter of vacuum drying, which represents the difference in vacuum degree between the outlet of the component and the inside of the container 2. is the vacuum degree of the i-th vacuum gauge measuring point, is the saturated vapor pressure of the working fluid being dried at room temperature (15℃~25℃), d is the judgment threshold of the dimensionless parameter y, and when y is less than d, it can be determined that the drying of the component is completed.

[0095] Regarding step S11: as the working medium evaporates, the vacuum degree in the container 2 continues to decrease. During the working medium evaporation process, the vacuum degree will have a plateau period. When the vacuum degree in the container 2 passes through the plateau period and continues to decrease, it means that the working medium is almost completely evaporated. At the same time, the vacuum degree is detected, and the determination is made based on the vacuum degree detection and drying determination device 8. To determine whether the drying is successful, first, the vacuum degree inside the container 2 and the product outlet reaches below the guaranteed vapor pressure of the current temperature of the working medium. If the drying is successful, then there is no large amount of working medium evaporating inside the product, and the vacuum degree at the product outlet must be close to the vacuum degree inside the container 2. Therefore, the given judgment criteria are: the vacuum degree at the product outlet and the vacuum degree inside container 2 When the pressure is less than one tenth of the saturated steam of the working fluid at the current temperature and the dimensionless parameters of the two vacuum degrees are less than d, it proves that the drying of the components is completed.

[0096] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0097] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A drying method for a blind cavity and micro-groove component drying device for a fluid circuit, characterized in that: The drying device comprises a container (2) for placing components to be dried; Gas source (1): used to provide clean, dry gas to the container (2); Hot air circulation module (3): heats the gas input from the gas source (1) into the container (2), and is also used for forced convection circulation of the heated gas to ensure that the temperature uniformity in the container (2) is less than 2°C; Gas compression supply and blowing module (4): used to pressurize the gas in the container (2) and blow and dry the components placed in the container (2) through the pipeline; Vacuum pump unit (5): used to evacuate the interior of the container (2); Vacuum infrared heating module (6): applies heat input to the components placed in the container (2) to increase the temperature of the components; The container (2) includes a tank door (21); The gas source (1) and the container (2) are connected via a gas supply pipeline, and the gas supply pipeline includes a main gas supply pipeline and a bypass gas supply pipeline; It also includes a concentration detection and drying determination device (7): used to detect the gaseous concentration of the working medium at the blow-off outlet of the component and the gaseous concentration of the working medium inside the container (2); The drying method comprises the following steps: Step S1: Use high-purity nitrogen to pressurize and blow out the interior of the blind cavity or micro-groove component to discharge the liquid working medium filled inside; Step S2: filling the blind cavity or micro-groove component with another liquid solvent that is mutually soluble and volatile with the working medium to perform mutual dissolution and replacement, and blowing out with nitrogen to carry out the non-volatile working medium; Step S3: placing the component to be dried in the container (2), connecting the air outlet of the component air supply pipe, and closing the tank door (21); Step S4: Open the gas source (1) to fill the container (2) with dry nitrogen; Step S5: Start the hot air circulation module to heat to the set temperature for hot air circulation drying, and dry for a certain time; Step S6: Start the compressed gas supply blowing module (4) to blow away the component products; Step S7: Open the exhaust valve to discharge the hot and humid nitrogen containing the working fluid steam after operation; Step S8: Repeat the steps S4 to S7 to determine whether the concentration of the working medium vapor contained in the high-purity nitrogen in the container (2) reaches the set value through the working medium concentration detection device and the drying determination device. If it reaches the set value, proceed to the next step. If it does not reach the set value, repeat the steps S4 to S7. Step S9: closing the hot air circulation module (3) and the gas compression supply and blowing module (4), discharging the hot and humid nitrogen containing the working fluid steam, and closing the outlet valve; Step S10: Start the vacuum unit, turn on the vacuum infrared heating module (6), and heat to the set temperature; Step S11: As the working medium evaporates, the vacuum degree in the container (2) continues to decrease. When the vacuum degree decreases to near the saturated vapor pressure of the working medium, the residual liquid working medium evaporates and the vacuum degree will have a plateau period. During the plateau period, the bypass gas supply line of the gas source (1) is opened to replenish high-purity nitrogen gas into the interior of the component, forming a micro-flow passing through the inner cavity of the component, carrying out the working medium gas molecules in the cavity of the component, reducing the working medium vapor partial pressure in the inner cavity of the component, and further increasing the evaporation rate of the working medium under low vacuum conditions; when the vacuum degree in the container (2) continues to decrease after passing through the plateau period, it indicates that the working medium is almost completely evaporated; at the same time, the value of the concentration detection and drying judgment device (7) is monitored. When the absolute values ​​of the blow-off outlet of the component and the concentration detection device inside the container (2) are reduced to a certain value, and the difference between the two values ​​is less than a certain ratio, it is proved that the drying of the component is completed; Step S12: Fill with high-purity nitrogen to restore normal pressure, open the exhaust port, open the tank door (21), take out the product, and complete the drying process.

2. The drying method of the blind cavity and micro-groove portion drying device for a fluid circuit according to claim 1, characterized in that: The outer wall of the container (2) is coated with a thermal insulation layer; A cold trap collector (22) is provided inside the container (2), and the cold trap collector (22) is provided at the communication port between the vacuum pump group (5) and the container (2).

3. The drying method of the blind cavity and micro-groove portion drying device for a fluid circuit according to claim 1, characterized in that: The main gas supply pipeline comprises a pressure reducing valve (11), a filter (12) and a pulse control valve (13) which are sequentially connected from the gas source (1) to the container (2); The bypass gas supply pipeline comprises a pressure reducing valve (11), a filter (12) and a micro-flow valve (14) which are sequentially connected from the gas source (1) to the container (2).

4. The drying method of the blind cavity and micro-groove portion drying device for a fluid circuit according to claim 3, characterized in that: The air supply pipeline also includes an air supply pipe extending into the container (2); The hot air circulation module (3) comprises an electric heating element (31) and a fan (32), and the electric heating element (31) is connected to the air supply pipe; The fan (32) is directly opposite to the component and is used for forced circulation of heating gas and hot air circulation drying of the component.

5. The drying method of the blind cavity and micro-groove portion drying device for a fluid circuit according to claim 4, characterized in that: The gas compression and air supply blowing module (4) comprises an air compressor, which compresses the gas in the container (2), and the outlet of the air compressor is connected to the air supply pipe.

6. The drying method of the blind cavity and micro-groove portion drying device for a fluid circuit according to claim 1, characterized in that: The concentration detection and drying determination device (7) comprises a concentration detector, and one or more concentration detectors are respectively placed at the blow-off outlet of the component and in the container (2).

7. The drying method of the blind cavity and micro-groove portion drying device for a fluid circuit according to claim 6, characterized in that: The judgment relationship of the concentration detection and drying judgment device (7) is as follows: For the hot air circulation stage: satisfy Enter the next stage; in, represents the concentration index of the ith concentration detection point; c represents the drying judgment threshold value of the set hot air circulation stage; For the vacuum heating stage: satisfy ; Determine whether the drying of the components is completed; Wherein, x is a dimensionless index parameter in the vacuum drying stage, representing the difference in the concentration or partial pressure of the working medium vapor at the blow-off outlet of the component and inside the container (2); a and b are both drying judgment thresholds in the vacuum heating stage.

8. The drying method of the blind cavity and micro-groove portion drying device for a fluid circuit according to claim 1, characterized in that: It also includes a vacuum degree detection and drying judgment device (8): used to detect the vacuum degree of the blow-off outlet of the component and the vacuum degree inside the container (2); The vacuum degree detection and drying judgment device (8) comprises a vacuum gauge, and at least one vacuum gauge is placed inside the container (2) and at the blow-off outlet of the component.

9. The drying method of the blind cavity and micro-groove portion drying device for a fluid circuit according to claim 8, characterized in that: The drying degree judgment relationship of the vacuum degree detection and drying judgment device (8) is as follows: satisfy ; Wherein, y is a dimensionless parameter of vacuum drying, which represents the difference in vacuum degree between the blow-off outlet of the component and the inside of the container (2). is the vacuum degree of the i-th vacuum gauge measuring point, is the saturated vapor pressure of the working medium at 15℃~25℃, d is the judgment threshold of the dimensionless parameter y, and when y is less than d, it is determined that the drying of the component is completed.

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